[larryskydives]

I have a 24 ft. Pontoon with a Johnson 140 on it. There seems to be a lot of ventilation when I throttle up fast when it gets to about 3000 rpm. I can let off and bring it back up slow and can then get to 4000 rpms when it starts again.I bought this pontoon used and believe it is not set up right. I was able to lower the motor on bolt hole to it's lowest position.Now for the prop - it has a 13 X 19 on it now.What are your thoughts, what should it be?

[Silvertip]

Are you sure its blowing out? It may be the hub is spinning inside the prop. Place a mark on the hub and another on the outer part of the prop. Make a run to create the problem. Then check to see if the two marks are still lined up. If not, the hub is spun and the prop needs to be repaired or replaced. It may also be that something under the pontoon is creating turbulence in the water flow to the engine.

[rickdb1boat]

And a 19" prop is too steep. 15" or 17" sounds more reasonable for a 24'er...